<template>
  <!-- 底部部分 => list有数据的时候，才展示  list.length > 0 -->
  <footer class="footer" v-if="list.length > 0">
    <span class="todo-count"
      ><strong>{{ of }}</strong
      >剩余</span
    >
    <ul class="filters">
      <li>
        <a
          @click="filter('all')"
          :class="{ selected: type === 'all' }"
          href="#/"
          >全部</a
        >
      </li>
      <li>
        <a
          @click="filter('active')"
          :class="{ selected: type === 'active' }"
          href="#/active"
          >进行中</a
        >
      </li>
      <li>
        <a
          @click="filter('completed')"
          :class="{ selected: type === 'completed' }"
          href="#/completed"
          >已完成</a
        >
      </li>
    </ul>
    <!-- 有已完成的任务，才需要显示这个按钮 -->
    <button v-if="isShow" class="clear-completed" @click="clear">
      清除已完成
    </button>
  </footer>
</template>

<script>
export default {
  props: {
    list: Array,
    type: String,
  },

  computed: {
    of() {
      // false未完成,的长度
      return this.list.filter((item) => item.flag === false).length;
    },
    isShow() {
      // 有已完成的显示,没有的隐藏
      return this.list.some((item) => item.flag === true);
    },
  },
  methods: {
    clear() {
      this.$emit("remove");
    },
    filter(type) {
      this.$emit("changeType", type);
    },
  },
};
</script>

<style></style>
